The table below shows recommended settings for standard T1 connections to your local exchange carrier.
Field
Value
Notes
Line Coding
b8zs
Use ami-zcs if b8zs is unavailable.
Signaling Mode
robbed-bit
Robbed-bit signaling gives you 56K bandwidth per channel. If you need a 64K clear channel for applications like asynchronous data transmission or remote administration access, use common channel signaling.
Framing
esf
Use d4 if esf is unavailable.
If you use b8zs line coding and esf framing, it will be easier to upgrade your T1 facility to ISDN should you want to. You can upgrade without reconfiguring external channel service units, and your service provider won’t have to reconfigure your network connection.
